The invention relates to pen-shaped syringes with automatic needle insertion, which syringes have an injecting system comprising a basic part carrying a medicine reservoir being at its distal end provided with a hypodermic needle and being at its proximal end closed by a piston, a dosing mechanism having a carrier engaging a cogging on a piston rod to advance this rod in the distal direction to press the piston into the reservoir a distance corresponding to a set dose when an injection button is pressed, the injection system being integrally displaceable in a housing by a spring which may be compressed and released to displace the injection system in the distal direction in the housing to insert the needle into the skin of a patient.
Such pen shaped syringes are used by patients who treat themselves by frequently injecting a medicine dose which may be set individually immediately before each injection, and the setting is deleted when the injection is performed. Often the same dose is used by a number of injections, and consequently some patients might wish for a syringe by which the dose does not have to be set before each injection. Especially patients to whom a reduced tactile motor function makes it difficult to perform the setting would appreciate a syringe by which a setting is not deleted by the injection, but is remembered until it is altered voluntarily.